Mechanical pump



Sept. 29, 1964 R. F. SMITH ETAL MECHANICAL PUMP 2 Sheets-Sheet 1 FiledJuly 5, 1961 4 INVENTORS RUSSELL F. SMITH .ELDON A. JOHNSON EDWARD M.MASON AGENT Sept. 29, 1964 R. F. SMITH ETAL MECHANICAL PUMP 2Sheets-Sheet 2 Filed July 5, 1961 v INVENTORS RUSSELL F. SMITH ELDON A.JOHNSON I EDWARD M. MASON W AGENT United States Patent O "'ce 3,150,601MECHANICAL PUIVEP Russell F. Smith, Ferguson, and Eldon A. Johnson andEdward M. Mason, St. Louis County, Mo., assignors to ACF Industries,Incorporated, New York, N.Y., a corporation of New Jersey Filed July 5,1961, Ser. No. 122,025 Claims. (Cl. 103-150) This invention relates topumps, and more particularly to a diaphragm pump of a type especiallysuitable for pumping automotive fuel to the carburetor for an internalcombustion engine, the diaphragm of the pump being operable by a drivefrom the engine.

This application isa continuation-in-part of application Serial No.764,978, filed October 2, 1958 and now US. Patent No. 3,001,773.

One of the problems occurring with conventional diaphragm fuel pumps isthe problem of vaporization of fuel in the pump, with the attendantpossibility of interruption of flow of fuel to the carburetor, thisbeing customarily referred to as vapor lock. It will be understood thatthe fuel is highly volatile, having a tendency to pass from the liquidto the vapor state, which tendency is of course increased by heating.Since the fuel pump is conventionally mounted on the engine to be driventhereby, heat is transferred from the engine to the pump, and thereby tofuel in the pump. Unless this heat is effectively dissipated, vapor lockmay occur due to vaporization of fuel in the pump.

Accordingly, one of the objects of this invention is the provision of apump which, while being of simple, economical construction, is adaptedeffectively to dissipate heat from the pump so as effectively to reducethe tendency for volatilization of fuel in the pump, thereby to reducethe possibility of vapor lock. In general, this is accomplished byutilizing a pump body of thin-walled heat-conductive construction suchas to provide for transfer of heat outward throughthe wall of the bodyat such a rate as substantially to reduce the tendency forvolatilization of fuel within the body. The pump'body is formed toprovide a pumping chamber and an intake cavity and a discharge body, andthe pump includes a diaphragm closing the pumping chamber, an intakecheck valve in themtake cavity anda discharge check valve in thedischarge cavity. With the body of thin-walled heat-conductiveconstruction, heat is effectively dissipated from the pumping chamberand from the intake and discharge'cavities, thereby maintaining fuel inthe pump in a relatively cool state to reduce the tendency towardvolatilization such as would otherwise be present. The pump body may beformed of relatively thin sheet metal, which provides for a simpleeconomical construction while at the same time providing for effectiveheat dissipation. Additionally, the outside surface of the body may bemade heat-reflective to decrease the absorbtion of heat by the body fromambient temperatures.

Further objects of the invention are the provision of means in thedischarge cavity or in both the discharge and intake cavities fordamping pulsations in pressure of fuel delivered by the pump, so as tomaintain a more uniform rate of delivery of fuel to the carburetor, andthe provision of an improved check valve construction such as to avoiddistortion of the check valves when they are assembled with the pumpbody, thereby to maintain the accuracy of the seats of the check valves.Other objects and features will be in part apparent and in part pointedout hereinafter.

The invention accordingly comprises the constructions hereinafterdescribed, the scope of the invention being indicated in the followingclaims.

3,150,601 Patented Sept. 29., 1964 FIG. 4 is an enlarged vertical crosssection of a check valve used in the pump;

FIG. 5 is a bottom plan of the FIG. 4 check valve;

FIG. 6 is a fragmentary vertical cross section of a pump similar to theFIG. 2 and including a first type of pulsation-damping means;

FIG. 7 is fragmentary vertical cross section similar to FIG. 6illustrating a second type of pulsation-damping means and alsoillustrating certain modifications in the pump construction;

FIG. 8 is a half-section in perspective of a modified version of thepulsation-damping means of FIG. 7; and

FIG. 9 is a fragmentary vertical cross section similar to FIG. 2illustrating another type of pulsation-damping means and alsoillustrating certain modifications in the pump construction.

' Corresponding reference characters indicate correspond partsthroughout the several views of the drawings. Referring to FIG. 1 of thedrawings, there is indicated at A an automotive vehicle having an engineE on which is mounted a fuel pump P of this invention. Fuel is de'livered from fuel tank T of the vehicle through a line L1 to the fuelpump P and delivered by the latter through a line L2 to the carburetor Cfor the engine. The carburetor is mounted on the intake manifold of theengine, and an air filter F is shown mounted on the air horn of thecarburetor.

As appears in FIGS. 1-3, pump P is a so-called in-' verted pump, i.e.,its inlet and outlet are located at the bottom of the pump.' As shown indetail in FIGS. 2 and 3, pump P'comprises a rocker arm housing 1 whichis open at one end (its left end as appears in FIG. 2), this end beingreferred to as the inner end of the housing. This housing is ofgenerally rectangular form in vertical cross section and of decreasingheight from its inner end'to its outer end (which is closed). At itsinner end it has a flange 3 for attaching it to the engine E. A rockerarm 5 is pivoted at 7 in the housing for rocking moton on a horizontalaxis transverse to the housing. Arm 5 has a portion 5a projecting out ofthe open inner end of the housing, and is biased to rock clockwise asviewed in FIG.

2 by a spring 9. 'When the pump is mounted on the engine, the free endportion 5a of the rocker arm is engaged by an engine-driven eccentric orcam 11. On rotation of the cam through half a revolution from its FIG. 2position (wherein the low point of the cam engages portion 5a of therocker arm), the rocker arm is rocked counterclockwise from its FIG. 2position against the bias of spring 9. The latter is adapted to returnthe arm thick flat flange 17 at the bottom. The bottom of thisflangeconstitutes a seating surface for the margin of an annular diaphragm 19consisting of a relatively thin disk of flexible fuel-resistantmaterial, such as a suitable synthetic rubber, which, when in unstressedcondition, is flat or substantially flat. The outer margin of thediaphragm is clamped against the bottom of flange 17 by a pump body 21which, as illustrated in FIG. 2, is of one-piece thin-Walled sheet metalconstruction, formed of shallow cup shape, having a bottom or end wall23 and a flaring, rounded annular peripheral wall 25 defining a pumpingchamber 26, with an outwardly extending annular flat flange 27 at thetop of wall 25, and a cylindric rim 29. The body 21 is maintained inassembly with head 13 by spinning the rim 29 over on flange 17 of thehead as indicated at 31, with the margin of the diaphragm clampedbetween flange 17 and flange 27 under suflicient pressure to provide afuel-tight seal all around the margin of the diaphragm.

The diaphragm is adapted to be pulled or flexed upward by adiaphragm-actuating rod 33 and to be flexed downward by a spring 35. Rod33 extends upward through head 13 and through the opening at the top ofthe head into the rocker arm housing 1. The rocker arm 5 has a slot 37at its end in housing 1 receiving the rod 33. The latter has a collar 39at its upper end engageable by this end of the arm 5. The rod extendsslidably through an oil seal and rod guide 41 held in an annular recessat the top of the head 13 by the reaction on a seal retainer ring 43 ofthe spring 35, this spring being a coil compression spring surroundingthe rod. The diaphragm is mounted on the lower end of the rod 33 betweena pair of circular plates 45 and 47, plate 45 being the upper plate andplate 47 the lower plate. upper plate is formed with an annularcorrugation or rib 49 forming a seat for confining the lower end ofspring 35. The upper plate is of larger diameter than the lower plateand the margin of the upper plate which overhangs the lower plate isflared outward and downward to provide a rim 51 constraining thediaphragm to have an annular, free, nonreversing loop 53. The lowerplate has a curved rim 55 engaging the loop. In the downward position ofthe diaphragm illustrated in FIG. 2, the outside of the loop engages therounded flaring wall of the pump body 21. When arm 5 is rockedcounterclockwise by cam 11, it lifts the rod and pulls the diaphragmupward. This loads the spring 35. Then when arm 5 rocks clockwise,spring is adapted to drive the diaphragm and rod downward.

The sheet metal pump body 21 is formed with two integral deep-drawnrounded-bottom cylindrical cupshaped projections 57 and 59 extendingdownward from the bottom Wall 23 of body 21 on opposite sides of thecenter of the bottom wall. Projection 57 defines an inlet passage orintake cavity 61 and projection 59 defines an outlet passage ordischarge cavity 63. An inlet nipple 65 is provided at the lower end ofprojection 57, and an outlet nipple 67 is provided at the lower end ofprojection 59. In FIG. 2, inlet nipple 65 is shown as a straight nipple,and outlet nipple 67 is shown as an elbow nipple. It will be understoodthat, in the installation shown in FIG. 1, supply line L1 is connectedto inlet nipple 65 and discharge line L2 is connected to outlet nipple67.

The nipples 65 and 67 are fixed to the respective deepdrawn projections57 and 59 by inserting the respective collared ends 66 and 68 into acentral aperture in the bottoms of the respective projections 57 and 59and swaging the metal of the projections tightly against the nippleends, as shown to form a fuel tight seal. The collared nipple ends 66and 68 each have grooves formed in the surface of the collars so thatthe swaged metal is pressed into the grooves to prevent a rotationaldisplacement of the nipples. The sheet metal construction of the pumpthus lends itself to a universal adjustment of the nipple 67, forexample, in 360 to accommodate any required directional departure of theinlet fuel line L2. In a similar manner nipple 65 may also be formedwith an elbow to accommodate any directional approach of inlet line L1.

The

This universal adjustability of the nipples 65 and 67 provides aflexibility of use with different engine arrangements, which is notavailable in pumps fabricated from castings.

An intake check valve 69 is provided in the intake cavity 61 and adischarge check valve 71 is provided in the discharge cavity 63. Nipple65 provides for connection of supply line L1 to intake cavity 61upstream from the intake check valve 69 and nipple 67 provides forconnection of discharge line L2 to discharge cavity 63 downstream fromthe discharge check valve 71. These check valves are of identicalconstruction. As shown in FIGS. 4 and 5, each check valve comprises acircular sheet metal valve seat 73 having a cylindric rim 75 sized for apress fit in either cavity 61 or cavity 63, as the case may be. Seat 73has a central hole 77 with an annular boss 79 around the hole extendingin the same direction as the rim 75. Surrounding the central hole is aseries of ports 31 arranged in a circle around the center hole. Thedimension of each of these ports as measured along the stated circle isless than the distance measured radially of the seat 73 from theperiphery of the center hole 77 to the periphery of the seat 73. Moreparticularly, the ports are circular holes of smaller diameter than thecenter hole. They are equally and closely spaced around the statedcircle at intervals such as to leave spoke-like portions 82 of the valveseat 73 between the ports with these spoke-like portions narrower thanthe diameter of the ports. Seat 73 is preferably dished inwardly to aslight extent in the direction in which rim 75 and boss 79 projecttherefrom (i.e., downwardly dished as viewed in FIG. 4). This dishingmay be of the order of 1 /2, for example. Fitted in the boss 79 is ahollow sheet metal stem 83 which is closed at its lower end as indicatedat 85 in FIG. 4. Stem 83 has an apertured mushroom head 87 at its otherend constituting a spring seat. A ring-shaped disk valve member 89,which may be made of a suitable fuel-resistant synthetic rubber forcushioned sealing, is slidable on the stem and is biased towardengagement with the valve seat by a coil compression spring 91surrounding the stem and reacting from the head 87. In assembling thestem with the valve seat, the stem 83 is pressed in the central hole 77in the valve seat and the closed end of the stem is deformed asindicated at 93 to lock the stem in the seat and seal the central hole.

The intake check valve 69 is pressed in the intake cavity 61 with itsstem 83 extending upward and the discharge check valve 71 is pressed inthe discharge cavity 63 with its stem extending downward (see FIG. 2).It has been found that, with the ports in the valve seat formed asherein described, rather than being formed as relatively long slots inthe valve seat, stresses such as would cause distortion of the valveseats during the operation of pressing the seats into the cavities areavoided, and the original accuracy of the seats is preserved. At thesame time, the total port area is adequate for flow of fuel.

In the operation of the pump shown in FIG. 2, diaphragm 19 is flexed upand down by the action of cam 11 and spring 35. On an upward (suction)stroke of the diaphragm, the intake check valve 69 opens and thedischarge check valve 71 closes, and fuel is drawn into the pumpingchamber 26 below the diaphragm. On a downward (discharge) stroke of thediaphragm, the intake check valve 69 closes and the discharge checkvalve 71 opens, and fuel is forced out through line L2 to thecarburetor. Since the pump body 21 is formed of sheet metal, it is ofthin-walled heat-conductive construction such as to provide for transferof heat outward therethrough at such a rate as substantially .to reducethe tendency for volatilization of fuel within the body, therebyreducing the possibility of vapor lock. In this respect, it will beobserved that heat transmission occurs not only through walls 23 and 25of pumping chamber 26 but also through the walls and bottoms ofprojections 57 and 59, all of which are thin-walled, so

that heat is dissipated at a relatively rapid rate. The rate may beincreased by making the outer surface of the pump body heat-reflective,as by bright zinc plating of the exterior of the pump body. With suchplating, heat is reflected from the body for cooler operation of thepump and increased transmission of heat from fuel in the pump body tothe exterior.

Making the pump body of sheet metal not only pro vides a thin-walledconstruction for effective heat dissipation, but also provides aneconomical construction, the pump body itself being economical tomanufacture and economical to assemble with the rocker arm housing 1,the assembly operation simply involving the spinning over of rim 29 ofthe pump body on flange 17 of the head 13. A typical pump body having adiameter (measured at rim 29) of three and one-half inches may be madeof suitable steel plate 0.035 inch thick, for example. In general, theadvantages of the invention may be a-t tained with a pump body having awall thickness less than 0.050 inch.

FIG. 6 illustrates a pump similar to that shown in FIG. 2 provided withmeans for damping pulsations in pressure of fuel delivered by the pumpso as to maintain a more uniform rate of delivery of fuel to thecarburetor. As shown in FIG. 6, the cup-shaped projections of the pumpbody 21 are drawn deeper than in FIG. 2, and are designated 57a and 59a.In each cup is press-fitted a partition 101 having a central hole 103and a circular series of ports 105 around the central hole 103. Theportion of the partition around the center hole is cupped as indicatedat 107 to form a seat for a hollow resilient compressible ball 109 whichmay be made, for example, of a suitable fuel-resistant synthetic rubber.In the intake cup 57a the partition is arranged with seat 107 extendingupward and ball 109 below the partition. In the discharge cup 59a, thepartition is arranged with seat 107 extending downward and ball 109above the partition. The hollow resilient compressible balls 109 actlike air chambers or air domes to damp pulsations of pressure of fuel inthe intake and discharge cavities by contract-ion and expansion thereof,and tend to equalize pressure of fuel delivered to the carburetor.

FIG. 7 illustrates a modification in which the cupshaped projections ofthe pump body 21 are constituted by separately formed cup members 57band 5%. Each of these has an outwardly extending rim 111 at its upperend and extends down through an opening 113 provided in the bottom wall23 of the pump body, the rims engaging the bottom wall 23 and beingsuitably soldered thereto. This three-piece type of construction for thepump body 21 has the advantage over the one-piece type of pump bodyshown in FIG. 6, for example, in that, for a given cup height, itpermits the cups to be arranged closer together, as may be desirable. Inthis respect, it will be observed that with deep-drawn integral cups asin FIG. 6, it is necessary that the cups be relatively widely spaced topermit deep drawing.

FIG. 7 also illustrate another type of pulsation damping meanscomprising an annular hollow resiliently compressible member 121 axiallypositioned in each projection 57b and 59b, each of these members beingmade, for example, of a suitable fuel-resistant synthetic rubber. Thecentral passages 125 through these members provide for flow of fuel, andpulsations are damped by contraction and expansion of the members, whichact like air chambers or air domes.

FIG. 8 illustrates a modification of the pulsation damping members ofFIG. 7, showing an annular resiliently compressiblemember 121a made ofclosed-cell foam rubber of a fuel-resistant variety. Such members may beconveniently obtained by segmenting an extruded tube of the closed-cellfoam rubber material. They are placed in cups 57b and 59b in the samemanner as members 121 shown in FIG. 7.

FIG. 9 illustrates another arrangement for pulsation damping on thedischarge side of the pump only. As shown therein, the intake cup,designated 57c, is a rela tively short cup (as in FIG. 2), formed as aseparate piece and soldered to the pump body as in FIG. 7. The dischargecup comprises a shell 131 having a cylindric upper end portion 133received in an opening in the bot-tom wall 23 of pump body 21 in thesame manner as in FIG. 7, and a flaring lower portion 135. The dischargecheck valve 71 is pressed into the cylindric portion 133. The flaringlower portion has an outwardly projecting flat annular flange 137 at itslower end constituting a seating surface for a diaphragm 139 made, forexample, of a suitable fuel-resistant synthetic rubber. The outer marginof the diaphragm is clamped against the bottom of flange 137 by the rim141 of an inverted dome 143 and the parts are held in assembly byspinning a rim 145 on flange 137 over on the rim 141 of the dome. Thediaphragm 139 and the dome provide an air chamber 147 sealed off fromthe shell 131, pulsations being damped by flexing of the diaphragm. Thedischarge nipple 149 is connected to shell 131 above the diaphragm 139.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

. As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

I claim:

1. A diaphragm pump for pumping a volatile liquid, said pump comprisinga pump head, a pump body secured to said pump head, said pump body beingformed from a single piece of sheet metal into a single walled cuphaving a circular flange around the lip of the cup, a diaphragm assemblyincluding a circular diaphragm of flexible fuel resistant materialextending across said pump body and having its peripheral margin clampedbetween said circular flange and said pump head, said body cup having anend wall and an annular peripheral wall between said end wall and saidcircular flange defining with said diaphragm a pumping chamber, saidbody having a pair of closed tubular projections extending outwardlyfrom said end wall and opening into said pumping chamber, said tubularprojections each having a passage through the wall thereof, a coilspring within said head biasing said diaphragm assembly toward said endwall, a circular plate coaxially fixed to said diaphragm between saidspring and said diaphragm, said plate extending across said pumpingchamber and having a marginal edge spaced from said annular cup wall andformed with a rim flared toward said pumping chamber for moving theannular portion of said diaphragm adjacent to the peripheral marginthereof against and into contact with said annular peripheral body wallto force fuel out of said pumping chamber into one of said tubularprojections, said dia phragm assembly including a rod to move saiddiaphragm assembly against said spring bias to move said annulardiaphragm portion away from said annular body wall to draw fuel intosaid pumping chamber from the other one of said tubular projections, aninlet check valve means within said other one of said tubularprojections for controlling fluid flow through said passage thereof, andoutlet check valve means for controlling the flow of fluid through saidpassage in said one of said tubular projections.

2. A diaphragm pump as set forth in claim 1 wherein said tubularprojections are formed as integral parts of said body.

3. A diaphragm pump as set forth in claim 1 wherein said body comprisesa first part formed to provide said annular peripheral wall and said endwall and second and third parts formed to provide said tubularprojections and secured to said end wall.

4-. A diaphragm pump for pumping a volatile liquid, said pump comprisinga pump head, a pump body secured to said pump head, said pump body beingformed from a single piece of sheet metal into a single walled cuphaving a circular flange around the lip of the cup, a diaphragm assemblyincluding a circular diaphragm extending across said pump body andhaving its peripheral margin clamped between said circular body flangeand said pump head, said body cup having an end wall and an annularperipheral wall between said end wall and said circular flange definingwith said diaphragm a pumping chamber, said body having a pair of sheetmetal closed tubular projections extending outwardly from said end walland opening into said pumping chamber, said tubular projections eachhaving a passage through the wall thereof, a coil spring within saidhead biasing said diaphragm assembly toward said end wall, a circularplate coaxially fixed to said diaphragm between said spring and saiddiaphragm, said plate extending across said pumping chamber and having amarginal edge spaced from said annular cup wall and formed with a rimflared toward said pumping chamber for moving the annular portion ofsaid diaphragm adjacent to the peripheral margin thereof against andinto contact with said annular peripheral body wall to force fuel out ofsaid pumping chamber into one of said tubular projections, saiddiaphragm assembly including means to move said diaphragm assemblyagainst said spring bias to move said annular diaphragm portion awayfrom said annular body wall to draw fuel into said pumping chamber fromthe other one of said tubular projections, an inlet check valve meanswithin said other one of said tubular projections for controlling fluidflow through said passage thereof, and an outlet check valve meanswithin the said one of said tubular projections for controlling the flowof fluid through said passage thereof, said peripheral body wall andsaid tubular projections being outer exposed walls of said pump.

5. A diaphragm pump as set forth in claim 4 wherein said tubularprojections are formed as integral parts of said body.

6. A diaphragm pump for pumping a volatile liquid, said pump comprisinga pump head having an opening with a flange therearound, a sheet metalpump body having an opening with a rim therearound mounted across saidflanged opening of said pump head, said head flange being relativelythick compared with the thickness of the sheet metal of said body, adiaphragm assembly including a circular diaphragm of flexible fuelresistant material extending across the opening of said pump body andhaving its peripheral margin clamped between said pump body rim and saidpump head flange, said sheet metal body rim enclosing said head flangeto secure said body to said head, said sheet metal body having an endwall and an annular peripheral wall between said end wall and saiddiaphragm defining with said diaphragm a pumping chamber, said bodyhaving a pair of cup-shaped sheet metal projections extending outwardlyfrom said end wall and opening into said pumping chamber, said cupshapedprojections each having a passage through the wall thereof, a coilspring within said head biasing said diaphragm assembly toward said endwall with the annular portion of said diaphragm adjacent to theperipheral margin thereof lying against said annular peripheral bodywall, said diaphragm assembly including a rod to move said diaphragmassembly against said spring bias, an inlet check valve means within oneof said cup-shaped projections for controlling fluid flow through saidpassage thereof, and outlet check valve means for controlling the flowof fluid through said passage in the other one of said cup-shapedprojections.

7. A diaphragm pump for pumping a volatile liquid, said pump comprisinga pump head having an opening with a flange therearound, a sheet metalpump body having an opening with a rim therearound mounted across saidflanged opening of said pump head, said head flange being thick relativeto the thickness of the sheet metal of said body, a diaphragm assemblyincluding a pair of circular plates and circular diaphragm of flexiblefuel resistant material coaxially mounted with its central portion fixedbetween said plates, said diaphragm extending across the opening of saidpump body and having its peripheral margin clamped between said pumpbody rim and said pump head flange, said sheet metal body rim enclosingsaid head flange to secure said body to said head, said sheet metal bodyhaving an end wall and an annular peripheral wall between said end walland said diaphragm defining with said diaphragm a pumping chamher withone of said pump assembly plates within said pumping chamber, said bodyhaving a pair of cup-shaped sheet metal projections extending outwardlyfrom said end wall and opening into said pumping chamber, saidcup-shaped projections each having a passage through the wall thereof, acoil spring within said head biasing said diaphragm assembly toward saidend wall with the annular portion of said diaphragm adjacent to theperipheral margin thereof lying against said annular peripheral bodywall, said one plate having a curved rim projecting into said pumpingchamber, the other one of said plates having a curved rim extending overthe rim of said one plate, said diaphragm extending between said rimsand being directed by said rims into an annular loop extending betweensaid plate rims and said annular peripheral body Wall, said diaphragmassembly including a rod connected to said plates to move said diaphragmassembly against said spring bias, an inlet check valve means within oneof said cup-shaped projections for controlling fluid flow through saidpassage thereof, and an outlet check valve means within the other one ofsaid cup-shaped projections for controlling the flow of fluid throughsaid passage thereof.

8. A diaphragm pump for pumping a volatile liquid, said pump comprisinga pump head, a pump body secured to said pump head, said pump body beingformed from a single piece of sheet metal into a single walled cuphaving a flange around the lip of the cup, a diaphragm assemblyincluding a pair of plates and a diaphragm coaxially mounted with itscentral portion fixed between said plates, said diaphragm extendingacross said pump body and having its peripheral margin clamped betweensaid body flange and said pump head, said body cup having an end walland an outwardly flaring wall between said end wall and said body flangedefining with said diaphragm a pumping chamber with one of said pumpassembly plates within said pumping chamber, said one plate having acurved rim projecting into said pumping chamber, the other one of saidplates having a curved rim extending over the rim of said one plate,said diaphragm extending between said rims and being directed by saidrims into a continuous loop extending between said plate rims and saidoutwardly flaring body wall, said body having a pair of cup-shaped sheetmetal projections extending outwardly from said end wall and openinginto said pumping chamber, said cup-shaped projections each having apassage through the wall thereof, an

outlet check valve means within one of said cup-shaped.

projections for controlling fluid flow through said passage thereof, andan inlet check valve means within the other one of said cup-shapedprojections for controlling the flow of fluid through said passagethereof, and a coil spring within said head biasing said diaphragmassembly toward said end wall with the outer wall of said diaphragm loopagainst and into contact with said outwardly flaring body wall to forcefuel out of said pumping chamber into said one of said cup-shapedprojections, said diaphragm assembly including a rod connected to saidplates to move said diaphragm assembly against said spring bias and tomove said diaphragm loop away from said outwardly flaring body wall todraw fuel into said pumping chamber from said other one of saidcup-shaped projections.

9. A diaphragm pump for pumping a volatile liquid, said pump comprisinga pump head, a pump body secured to said pump head, said pump body beingformed from a single piece of sheet metal into a single walled cuphaving a circular flange around the lip of the cup, a diaphragm assemblyincluding a pair of circular plates and a circular diaphragm coaxiallymounted with its central portion fixed between said plates, saiddiaphragm extending across said pump body and having its peripheralmargin clamped between said circular body flange and said pump head,said body cup having an end wall and an annular outwardly flaring wallbetween said end wall and said circular flange defining with saiddiaphragm a pumping chamber with one of said pump assembly plates withinsaid pumping chamber, said one plate having a curved rim projecting intosaid pumping chamber, the other one of said plates having a curved rimextending over the rim of said one plate, said diaphragm extendingbetween said rims and being directed by said rims into a continuousannular loop extending between said plate rims and said outwardlyflaring body wall, said body having a pair of cup-shaped sheet metalprojections extending outwardly from said end wall and opening into saidpumping chamber, said cup-shaped projections each having a passagethrough the Wall thereof, an outlet check valve means within one of saidcup-shaped projections for controlling fluid flow through said passagethereof, and an inlet check valve means within the other one of saidcup-shaped projections for controlling the flow of fluid through saidpassage thereof, a coil spring within said head biasing said diaphragmassembly toward said end wall for moving the outer wall of saiddiaphragm loop against and into contact with said outwardly flaring bodywall to force fuel out of said pumping chamber into said one of saidcup-shaped projections, and means to move said diaphragm assemblyagainst said spring bias and to move said diaphragm loop away from saidoutwardly flaring body wall to draw fuel into said pumping chamber fromsaid other one of said cup-shaped projections.

10. A diaphragm pump for pumping a volatile liquid, said pump comprisinga pump head, a pump body secured to said pump head, said pump body beingformed from a single piece of sheet metal into a single thin walled cuphaving a circular flange around the lip of the cup, a diaphragm assemblyincluding a pair of circular plates and a circular diaphragm coaxiallymounted with its central portion fixed between said plates, saiddiaphragm extending across said pump body and having its peripheralmargin clamped between said circular body flange and said pump head,said body cup having an end wall and an annular peripheral wall betweensaid end wall and said circular flange defining with said diaphragm apumping chamber with one of said pump assembly plates within saidpumping chamber, said one plate having a curved rim projecting into saidpumping chamber, the other one of said plates having a curved rimextending over the rim of said one plate, said diaphragm extendingbetween said rims and being directed by said rims into a continuousannular loop extending between said plate rims and said annularperipheral body wall, said body having a pair of tubular sheet metalextensions formed outwardly from said end wall and each opening at oneend into said pumping chamber, said tubular extensions each being closedand having a passage through the wall thereof, an outlet check valvemeans within one of said tubular ex tensions for controlling fluid flowthrough said passage thereof, and an inlet check valve means within theother one of said tubular extensions for controlling the flow of fluidthrough said passage thereof, a coil spring within said head biasingsaid diaphragm assembly toward said end wall for moving the outer wallof said diaphragm loop against and into contact with said annularperipheral body wall to force fuel out of said pumping chamber into saidone of said tubular extensions, and means to move said diaphragmassembly against said spring bias and to move said diaphragm loop awayfrom said annular body wall to draw fuel into said pumping chamber fromsaid other one of said tubular extensions, said annular peripheral bodywall and said tubular extensions being outer exposed walls of said pump.

References Cited in the file of this patent UNITED STATES PATENTS406,273 Everett July 2, 1889 1,976,520 Rockwell Oct. 9, 1934 2,803,265Coffey Aug. 20, 1957 2,840,003 Johnson et al. June 24, 1958 2,856,862Korte Oct. 21, 1958 2,902,988 Rippingille Sept. 8, 1959 2,905,097Johnson Sept. 22, 1959 2,918,091 Borden Dec. 22, 1959 2,969,745 Johnsonet a1. Jan. 31, 1961 FOREIGN PATENTS 621,906 Canada June 13, 1961 83,399Sweden Mar. 14, 35

1. A DIAPHRAM PUMP FOR PUMPING A VOLATILE LIQUID, SAID PUMP COMPRISING APUMP HEAD, A PUMP BODY SECURED TO SAID PUMP HEAD, SAID PUMP BODY BEINGFORMED FROM A SINGLE PIECE OF SHEET METAL INTO A SINGLE WALLED CUPHAVING A CIRCULAR FLANGE AROUND THE LIP OF THE CUP, A DIAPHRAGM ASSEMBLYINCLUDING A CIRCULAR DIAPHRAGM OF FLEXIBLE FUEL RESISTANT MATERIALEXTENDING ACROSS SAID PUMP BODY AND HAVING ITS PERIPHERAL MARGIN CLAMPEDBETWEEN SAID CIRCULAR FLANGE AND SAID PUMP HEAD, SAID BODY CUP HAVING ANEND WALL AND AN ANNULAR PERIPHERAL WALL BETWEEN SAID END WALL AND SAIDCIRCULAR FLANGE DEFINING WITH SAID DIAPHRAGM A PUMPING CHAMBER, SAIDBODY HAVING A PAIR OF CLOSED TUBULAR PROJECTIONS EXTENDING OUTWARDLYFROM SAID END WALL AND OPENING INTO SAID PUMPING CHAMBER, SAID TUBULARPROJECTIONS EACH HAVING A PASSAGE THROUGH THE WALL THEREOF, A COILSPRING WITHIN SAID HEAD BIASING SAID DIAPHRAGM ASSEMBLY TOWARD SAID ENDWALL, A CIRCULAR PLATE COAXIALLY FIXED TO SAID DIAPHRAGM BETWEEN SAIDSPRING AND SAID DIAPHRAGM, SAID PLATE EXTENDING ACROSS SAID PUMPINGCHAMBER AND HAVING A MARGINAL EDGE SPACED FROM SAID ANNULAR CUP WALL ANDFORMED WITH A RIM FLARED TOWARD SAID PUMPING CHAMBER FOR MOVING THEANNULAR PORTION OF SAID DIAPHRAGM ADJACENT TO THE PERIPHERAL MARGINTHEREOF AGAINST AND INTO CONTACT WITH SAID ANNULAR PERIPHERAL BODY WALLTO FORCE FUEL OUT OF SAID PUMPING CHAMBER INTO ONE OF SAID TUBULARPROJECTIONS, SAID DIAPHRAGM ASSEMBLY INCLUDING A ROD TO MOVE SAIDDIAPHRAGM ASSEMBLY AGAINST SAID SPRING BIAS TO MOVE SAID ANNULARDIAPHRAGM PORTION AWAY FROM SAID ANNULAR BODY WALL TO DRAW FUEL INTOSAID PUMPING CHAMBER FROM OTHER ONE OF SAID TUBULAR PROJECTIONS, ANINLET CHECK VALVE MEANS WITHIN SAID OTHER ONE OF SAID TUBULARPROJECTIONS FOR CONTROLLING FLUID FLOW THROUGH SAID PASSAGE THEREOF, ANDOUTLET CHECK VALVE MEANS FOR CONTROLLING THE FLOW OF FLUID THROUGH SAIDPASSAGE IN SAID ONE OF SAID TUBULAR PROJECTIONS.